Information recording and/or reproducing apparatus and optical recording medium

Abstract: An information recording and/or reproducing apparatus (31) which can prohibit an optical head (30) from trying to access to a data track which does not exist on the optical recording medium (1). The information recording and/or reproducing apparatus (31) is used with an optical recording medium (1) having a plurality of tracks. The information recording and/or reproducing apparatus (31) comprises an optical head (30) which irradiates the optical recording medium (1) with a light beam and detects reflected light from the optical recording medium (1), a means for controlling the apparatus so as to read information about a number of the tracks of the optical recording medium (1), and memorise the information as an initial action. The optical head (30) is moved by the driving means within a range according to the memorised information.

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to an information recording and/or reproducing apparatus capable of recording information on an optical recording medium with a light beam, or reproducing information from an optical recording medium with a light beam. The invention also relates to an optical recording medium capable of recording and/or reproducing information with a light beam. Related Background Art Hitherto, as an information recording medium for recording and/or reproducing information, there have been known magnetic recording media capable of recording and/or reproducing information magnetically (for example, floppy disks and magnetic cards), and optical recording media capable of recording and reproducing information with a light beam. There has been known a disk-like or tape-like medium for use as an optical recording medium. It is considered that optical cards will be used in many ways, because of easy productivity, good portability, and a good accessibility. Figure 1 is a plan view of a typical conventional optical recording medium as, for example, disclosed in Japanese Laid-Open Patent Application JP-A-02-203467. Referring to Figure 1, 1 is an optical card having a rectangular plane shape, with a plurality of tracking tracks 2 running parallel to each other. Between each pair of tracking tracks 2 there is provided data track 3 in which information is recorded with a light beam, there being a plurality of data tracks 3 running parallel to each other. The tracking tracks 2 are used for registration of the position of the recording light beam and/or reproducing light beam when recording data in the data tracks 3 or reproducing data recorded in the data track 3. At both ends of the data track 3 there is a track identifier part 4 (hereinafter called "track ID part 4"). The track ID part 4, contains information that shows a position of each data track 3 and/or address information relating to the data track. This information is previously recorded in the track ID part 4, ie. is preformatted. Each data track 3 is divided into one or more minimum recording sectors. Information is recorded in the optical card described above by scanning a light beam modulated in accordance with the information on the data track 3 and focused to a small spot on the card, and making an optically detectable mark in the recording layer. Any information recorded on the optical card is reproduced by scanning on the data track a light beam having a fixed power which is not capable of recording, and detecting a difference of a quantity of reflected light or transmitted light between the mark and another part of the card. An information recording and/or reproducing apparatus which records information on an optical card or reproduces information recorded on the optical card may have automatic focusing control means that controls the size of light spot on the optical card automatically, and automatic tracking control means that controls the position of the light spot automatically. Herebefore, an outline of a conventional optical card and a conventional information recording apparatus is given. Recently, however, there has been suggested a hybrid card, which has not only an optical recording layer but also other information storage means, for example, an IC module, a magnetic stripe or embossed visible information. Furthermore, there have been various kinds of optical cards that have different recording capacity, that is having a different number of data tracks. Figures 2(a)-(c) are examples of typical views of such optical cards. Figure 2(a) shows an optical card which has an optical recording area 10 covering almost the whole surface. Figure 2(b) shows an optical card having visible information (embossed "optical card") with the optical card's recording area 10 being decreased compared to the Figure 2(a) card. Figure 2(c) shows an optical card having an IC module 11 so as to have both functions of an optical card and an IC card, with the optical card's recording area 10 being decreased so as to accommodate the IC module. However, in practice with such various optical recording medium having different recording capacity there is a problem as follows. Access of the recording light beam and/or reproducing light beam to the data track 3 is usually achieved using the information recorded in the track ID part which shows a physical position of the data track. Thus, when the recording and/or reproducing apparatus accepts a track number to be accessed in some form from an overall controlling means (for example, a host computer) the recording and/or reproducing apparatus searches the data track to be accessed in accordance with the information of track ID part to access a desired data track. Thus, hitherto, when the recording and/or reproducing apparatus accepts a track number, which the optical card to be read does not have, from the overall control means, the apparatus tries to access the track. As a result the automatic focusing control and/or automatic tracking control is out of control, and there a recording and/or a reproducing error may happen a lot time may elapse before the controls resume. In JP-A-2-203467 described above, the applicant of the present invention discloses an information recording reproducing apparatus for plural types of optical recording medium having a discriminating means for discriminating between plural types of optical medium, and control means for controlling an area to be recorded or reproduced in accordance with the result of the discrimination by the discriminating means. However, there is no disclosure about a control method for accommodating plural types of optical recording means which have different numbers of tracks. JP-A-62-239345 discloses an information recording medium provided an optically detectable mark which shows a kind of an optical recording medium at a data track. However, there is no disclosure of an optical recording medium which complies with the purpose of the present invention. EP-A-0 278 760 discloses an optical card reading/writing apparatus in which each track on the card has an address record area on which address data for the track is recorded including a track number. Prior to reading or writing, an address data recognising circuit is used to recognise the track number in order to enable the optical head to access the track. SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a high reliability information recording and/or reproducing apparatus in which the development of errors is at least reduced even though recording and/or reproducing on various different kinds of optical recording mediums. Another object of the present invention is to provide an optical recording medium which enables an information recording and/or reproducing apparatus to recognise the kind of optical recording medium without providing any special mark which decreases the recording capacity of the optical recording medium. Another object of the present invention is to provide an optical recording medium which enables an information recording and/or reproducing apparatus to recognise the type of optical recording medium without always providing any special mark on the optical recording medium. According to a first aspect of the present invention, there is provided an apparatus for performing at least one of the functions of recording information on and reproducing information from an optical recording medium having a plurality of tracks, comprising: an optical head for irradiating the optical recording medium with a light spot and detecting reflected light from the optical recording medium; means for moving the light spot to a desired track; and means for controlling the apparatus to read information about the number of tracks on the optical recording medium, and to memorise the information as an initial action, and then for controlling the moving means to move the light spot within a range dependent on the memorised information, the apparatus being characterised in that the means for controlling the apparatus is arranged to compare a track number to be accessed with the range, and to produce an error signal without moving the light spot towards the track when the track number is not within the range. According to a second aspect of the present invention, there is provided a method of performing at least one of the operations of recording information on and reproducing information from an optical recording medium provided with a plurality of data tracks having information about the number of tracks, the method comprising the steps of: providing an apparatus effective to perform at least one of the functions of recording information on and reproducing information from said information recording medium, the apparatus comprising: an optical head and a driving means effective to move the optical head to a desired data track, inserting said information recording medium into the apparatus; reproducing the information and memorising the range of accessible tracks on the information recording medium according to the information on the tracks; comparing a track address which is indicated by an input signal to the apparatus to be within the range; moving the optical head to a data track having the track address when the track address is within the range to record information; and sending out an error signal without moving the optical head when the track address is not within the range. A number of embodiments of the invention will now be described with reference to the accompanying drawings by way of example only. Brief Description of the Drawings Figure 1 is a typical plan view for illustrating a conventional optical card; Figure 2(a) to (c) illustrates various kinds of optical cards; Figure 3 shows an embodiment of a block diagram of the information recording and/or reproducing apparatus of the present invention; Figure 4 illustrates an optical card providing with a mark for indicating the kind of optical card; Figure 5 shows a flow chart illustrating an initial action when inserting an optical card to the information recording and/or reproducing apparatus; Figure 6 shows a flow chart illustrating a recording and/or reproducing process of the optical card according to an embodiment of the present invention; Figure 7 illustrates a composition of a field of an optical card's track ID part according to the first embodiment of the present invention; Figure 8 illustrates a composition of a field of an optical card's track ID part according to a second embodiment of the present invention; Figure 9(a) and (b) illustrate a composition of optical cards according to a third embodiment of the present invention; and Figure 10(a) and (b) are schematic views illustrating optical cards according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, an embodiment of the present invention will be explained in more detail with reference to the Figures. Figure 3 is a block diagram of an information recording reproducing apparatus in accordance with an embodiment of the present invention. Referring to Figure 3, the information recording reproducing apparatus indicated as 31 is generally called an "optical card drive" an apparatus for recording information in an optical card and/or reproducing information recorded in an optical card. The optical card drive 31 is connected to a host computer 32 as an upper control means. The optical card 1 is preferably an optical card of the form shown in Figure 4, of which recorded information about a number of the tracks is included in an optically detectable form. The information recording and/or reproducing apparatus 31 comprises a means (not shown in Figure 3) for conveying the optical card 1 into the apparatus, a means for moving the optical card 1 reciprocally in the direction "R" shown in Figure 3, and means for ejecting the optical card from the apparatus 31. In Figure 3, the means for moving the optical card 1 is shown as a motor 37. The apparatus 31 has an optical head 30 which forms a light spot on the optical card while recording and/or reproducing, and detects reflected light from the optical card. The apparatus 31 includes an optical system 38 comprising a light source and a lens, which directs a light beam on the optical card 1. A light detector 39 detects the reflected light from the optical card 1. The apparatus is also provided with an actuator 40 for automatic focusing control, and a further actuator 41 for automatic tracking control. The actuator 40 is for moving a part of the optical system 38 to change a focal point of the light beam in the direction of "Z" shown in Figure 3, that is the vertical direction toward the plane of the optical card 1, to automatic focusing. The actuator 41 is arranged to move part of optical system 38 so as to move the focal point slightly in the direction of "Y" shown in Figure 1 such that the light spot crosses the tracks, ie. perpendicular to the direction "R" and the direction "Z", to automatic tracking. Further, the apparatus is provided with a motor 36 for moving the optical head as a means for moving the optical head 30 in the direction "Y" to move the beam spot to desired track. The apparatus is provided with a modulator/demodulator 35 which modulate an information signal which shows information to be recorded to the optical card 1 and outputs the modulated information signal to the optical system 38, and which demodulates a signal from the light detector 39 and outputs a demodulated signal. The light beam from the light source in the optical system 38 is modulated by a modulated signal from the modulator/demodulator 35, thus information corresponding to the information signal is recorded on the optical card 1. The apparatus is also provided with an automatic focusing and automatic tracking controller 34 effective to move the actuators 40 and 41 according to a signal from the light detector 39 and the modulated signal from the modulator/demodulator 35. The controller 34 is for deciding a control quantity of each actuator 40 and 41 according to the output from the light detector 39, and for controlling the automatic focusing and automatic tracking. The modulated signal is used as a reference signal of an output signal from the light detector 39. Further, the apparatus is provided with a microprocessor unit (MPU) 33 for controlling the apparatus 31 totally, and controlling communication of data between the host computer 32 and the apparatus 31. The MPU 33 comprises a read only memory (ROM) and random access memory (RAM). The MPU 33 controls the motors 36 and 37, and controls a movement of the optical head 30 in accordance with a number of track which recognised to the apparatus 31 when the optical card 1 inserts the apparatus 31. That is, the MPU 33 keeps information about a number of tracks which are recognised by the apparatus 31 by the initial action of the insertion of the card 1 into the apparatus 31. Where the apparatus is going to access a desired track for recording and/or reproducing according to the instruction from the host computer 32, the MPU reads the information about the number of tracks from the RAM, and controls a movement of the optical head in the direction that crosses the tracks within the information about the number of the track. Next, a preferred embodiment of the present invention will be explained in more detail. Firstly, the initial action at the insertion of the optical card 1 will be explained with reference to Figure 5. In the present embodiment, an optical card provided with an optically detectable mark which shows the tracks number type of the optical card is used, and hereinafter, a type of card having a particular number of tracks is called "card type". The mark which shows the card type is the same as the mark 5 shown in Figure 4. Referring to Figure 5, in the step 101, the apparatus 31 checks whether the optical card has been inserted to the apparatus 31, and if it has not been inserted, the apparatus waits for insertion of the optical card 1. When the apparatus recognises that the optical card 1 has been inserted, the MPU 33 controls the motor 36 for moving the optical head 30 so as to move the optical head 30 in the direction "Y" and thereby move the light beam spot to the track provided with the mark (in the Figure 4, the track provided with the mark is a data track between tracking track 2(n-2) and 2(n-3). Then, in the step 102, the MPU 33 controls the motor 37 for moving the optical card 1 to scan the light beam spot on the track, and read the mark. In the step 103, the MPU 33 analyses the number of tracks on the optical card 1 and the card type and memorises the result in the RAM as an accessible range. The accessible range means information of the range of real tracks that the optical head can actually access. The information shown may correspond to the accessible range as follows, for example, the card type is "1", then the accessible range is "from track number 1 to track number 1100", and the card type is "2", then the accessible range is "from track number 1 to track number 2500". The relation between the card type and the accessible range may preferably be prerecorded in ROM of the MPU 33. Hereinabove, the initial action is finished. Secondly, a recording and/or reproducing process will be explained with reference to Figure 6. Referring to Figure 6, in the step 201, when the host computer 32 instructs the apparatus 31 to record information in the optical card 1, or to reproduce information recorded in the optical card 1, the MPU 33 judges whether the track address to be recorded or to be reproduced, which is directed from the host computer 32 is within the accessible range of the optical card 1 inserted in the apparatus 31. This judgement is done by comparing the directed track address to the accessible range recorded in the RAM during the initial action described above. In step 205, if the directed track address is not within the accessible range, the MPU 33 sends back an error signal to the host computer 32 without moving the optical head 30 toward the directed track, and finishes the accessing process. In step 202, if the directed track address is within the accessible range, the apparatus 301 records an information in the optical card 1 or reproduces an information recorded in the optical card 1. The action for recording and/or reproducing is done as follows. The MPU 33 controls the motor 36 to move the optical head 30 in the direction "Y", and to move the light beam to the directed track, and controls the motor 37 to scan the light beam over the directed track. When the above action is done, the automatic focusing control and automatic tracking control is carried out. In step 203, the MPU 33 checks whether the recording/reproducing is carried out correctly by processing an error correcting code. In step 204, if the recording/reproducing is carried out correctly, the MPU 33 send back a signal that the action is finished correctly to the host computer 32, to finish the processing. In step 206, if the recording/reproducing is not carried correctly, the MPU 33 send back a recording/reproducing error signal to the host computer 32, to finish the processing. According to the above embodiment, processing is performed by analysing the card type read during the initial action, and memorising an accessible range to the RAM. However, processing is not limited to the above embodiment, but may, for example, be performed by memorising a card type itself in the RAM, operating an accessible range from the card type when recording/reproducing the information, and comparing the directed track address to the accessible range. In the present invention, the optical card including information about the number of tracks as an optically detectable mark is not limited to the optical card used in the above embodiment. For example, other optical cards on which are recorded the number of tracks, or the accessible range of tracks as a value on at least one area of the card may be used. This information may be recorded as other than an optically detectable mark, for example a magnetic or mechanically detectable mark or marks may be used. Processing may be done by memorising the number of tracks or accessible range itself in the RAM, and comparing a directed track number to the value memorised in the RAM. Hereinafter, an optical recording medium having a preferred structure according to an embodiment of the present invention will be explained with reference to Figures 7 to 10. Figure 7 is a schematic view for illustrating a composition of track ID part 4 of one embodiment of an optical card according to the present invention. This optical card has an area 72 which shows a card type in the track ID part 4, and in this respect, this optical card is different from the optical card shown in Figure 1. The track ID part 4 comprises a preamble part (PRA) which is a pattern for synchronous pull-in of generating a self reproducing clock, synchronous signal field (S), an identification field (ID), an error correcting code field (ECC), synchronous signal field (S) and a preamble part (PRA) in this order. The identification field (ID) comprises an area 71 which shows a track address, and an area 72 which shows a card type. The synchronous field (S) is provided for identifying the head of the area 71 which shows the track address. The error correction code (EEC) is a field provided with an error correction code for increasing the reliability of reproducing the track ID information. The preamble part (PRA) and the synchronous signal field (S) is provided at both ends of the track ID part 4 so as to be capable of reproducing information recorded in the track ID part 4 from both directions. The number of tracks on the optical card is generally 3500 to 4000, even though the optical card has a recording area which covers almost whole surface like the optical card shown in Figure 2(a). Thus, an area of 12 bits is enough for recording the track address in the track ID part 4. On the other hand, it is preferable to treat information to be recorded in the optical card in blocks of 8 bits. Thus, an area of 2 bytes (= 16 bits) is secured in the track ID part 4. The inventors of the present invention consider that 12 information bits is enough for indicating a track address of an optical card. The optical card of the present embodiment is characterised in having a track ID part provided with an area 71 which indicates a track address and an area 72 which indicate a card type. Preferably 12 information bits are used as the area 71, and 4 information bits as the area 72. The information recording/reproducing apparatus can recognise the card type of the optical card inserted in the apparatus by reading the information recorded in the area 72 of track ID part 4. In case the area 72 has 4 information bits, it can indicate 16 types of optical card, which is enough for practical use. According to the present embodiment, because of recording information about a card type in the area that is not used in the optical card heretofore in use, it is not necessary to provide a mark for showing the card type at a data track as described in JP-A-62-239345, and thus the recording capacity of the optical card is not decreased. The area 72 may preferably be provided at each track ID part 4, so as to avoid it being necessary to reproduce a specific track of the optical card to recognise a card type and it being possible to recognise a card type even if the apparatus do not reproduce every track ID part 4. Thus recording and/or reproducing can be performed quickly. Figure 8 is a schematic view for illustrating the composition of a track ID part 4 of a second embodiment of an optical card according to the present invention. This optical card is different from the composition of identification field (ID) in the track ID part 4. That is, the optical card according to the second embodiment has an identification field (ID) comprising an area 81 which shows a track address, and an area 82 which shows a number of track. Each area has a capacity of 2 bytes. In the area 81, the track address of each data track, for example, the track number, is recorded in the form of binary code, and in the area 82, the number of the data tracks is recorded in the form of binary code. The information recording reproducing apparatus can identify the number of tracks by reproducing the area 82. According to this embodiment, it is possible to make the apparatus identify all kinds of optical cards having different numbers of tracks by recording the number of tracks directly, and it is possible to deal with an increase of the number of tracks in the future without changing the format of the optical card. Further, in this embodiment, the identification field (ID) has a capacity of 4 bytes, so that the identification field (ID) is larger than the identification field of the optical card of the first embodiment by 2 bytes. If the length of 1 bit is 5 µm, the length of the identification field of the present embodiment is longer than that of the first embodiment by 80 µm. According to this embodiment, the area 82 may preferably be provided at each track ID part 4 so that it is not necessary to reproduce a specific track of the optical card to identify a number of tracks. Thus, recording and/or reproducing can be done quickly. Figure 9(a) and 9(b) are typical views for illustrating the composition of a third embodiment of an optical card according to the present invention. Referring to Figure 9(a), the optical card has 2500 data tracks 3, and has track ID parts 4L,4R at both ends of each data track, with a track number corresponding to each data track being recorded in the track ID part. In Figure 9(a), each track number is indicated as a value in order to explain the optical card of this embodiment, but in practice the track number will be recorded in the track ID part 4 in the form of binary code. Referring to Figure 9(a), the track numbers are recorded in the sequence 0 to 2499 from the lower data track towards the upper data track in the track ID parts 4L provided at the left end of each data track. On the other hand, the track numbers recorded in the sequence 0 to 2499 from the upper data track towards the lower data track in the track ID parts 4R are provided at the right end of each data track. Thus, referring to the same data track, the sum of the track number recorded in the track ID part 4L and the track number recorded in the track ID part 4R is always 2499. This value is a maximum value of the track number, and corresponds to the numbered data tracks 0 to 2499. This value corresponds a number of tracks of the optical card according to the third embodiment. That is, referring to the optical card, the sum of the track number recorded in the track ID part 4L and the track number recorded in the track ID part 4R equals a value equal to the number of the data tracks minus 1. If however, the data tracks are numbered from 1, the sum of the track number recorded in the track ID part 4L and the track number recorded in the track ID part 4R will equal the number of data tracks plus 1, that is 2501. Referring to Figure 9(b), the optical card has 1100 data tracks 3, and has track ID parts 4L,4R at both ends of each data track, and a track number corresponding to each data track is recorded in the track ID part. In Figure 9(b), each track number is again indicated as a value to explain the optical card of this embodiment, but in practice the track number will be recorded at the track ID part 4 in the form of binary code. Referring to Figure 9(b), track numbers are recorded in each track ID part 4L from upper data track toward lower data track to be numbered 1099,1098,1097, ..., 3,2,1,0. Track numbers are recorded in each track ID part 4L from the upper data track towards the lower data track in the sequence 0,1,2,3,...,1097,1098,1099. Referring to this optical card, the sum of the track number recorded in the track ID part 4L and the track number recorded in the track ID part 4R is always 1099, this value equalling the maximum value of track number. As described above, where the track numbers are recorded in the track ID parts 4L and 4R in a sequence from the same number at the track ID port 4L, and are numbered in the reverse sequence and the track ID part 4R, the sum of the track number recorded in the track ID part 4L and the track number recorded in the track ID part 4R always corresponds to the number of tracks, and will be different among optical cards having different number of tracks. Thus, when an optical card as shown in Figure 9(a) or Figure 9(b) is inserted into the information recording and/or reproducing apparatus, the apparatus can identify the type of optical card from the sum of the track number recorded in the track ID part 4L and the track number recorded in the track ID part 4R. In this embodiment, it is not necessary for the apparatus to read specific data track's track ID parts, as the apparatus can identify a type of an optical card by reproducing the desired data track's track ID parts 4L and 4R. Accordingly, the apparatus can quickly record and/or reproduce information using an optical card according to this embodiment. Hitherto, there have been known optical cards having track ID parts at both ends of each data track, with the same track number being recorded at each end, because the information recording and/or reproducing apparatus is thus able to identify the track number before scanning the data track whichever side the apparatus starts scanning the data track from. In an optical card according to this embodiment, the track numbers recorded in the track ID part 4L and a track number recorded in the track ID part 4R are different at the same data track. Thus, it may be preferable to identify to the apparatus either the track number recorded in track ID part 4L or recorded in track ID part 4R as a reference track number, and whose track number is reproduced which is not the identified reference number, the reference track number be produced by the apparatus from the reproduced track number and the number of data tracks which is calculated by the apparatus from the track number recorded in the track ID parts 4L and 4R. For example, referring to the optical card shown in Figure 9(a), where the track number recorded in track ID part 4L is defined as the reference track number of each data track, and the apparatus firstly reproduces the track number of track ID part 4R firstly, the track number may be subtracted from 2499 to provide a reference track number. In case that the track number of track ID part 4R is 2496, the reference track number is provided as follows: 2499 - 2496 = 3 This value coincides with the reference track number recorded in track ID part 4L. As described above, by providing the apparatus with an operating means, the apparatus can identify a track number of each data track even when the apparatus reproduces the data track from the other side than that in which the track numbers are recorded. Hitherto, in known optical cards the automatic tracking control means has been known to become out of control due to dust or flaw attached to a surface of the optical card, causing the optical head to miss a data track during recording and/or reproducing, the optical head then starting to scan other data track uncontrollably. Hitherto, such an error can be detected, because of the difference between the track number which is reproduced before scanning and the track number which is reproduced after scanning. In an optical card according to this embodiment of the invention, the error described above can be detected because the sum of the track number which is reproduced before scanning and the track number which is reproduced after scanning is different from the total number of data tracks. In the embodiment described herebefore, the track number recorded in the track ID part 4L is numbered from the lowest data track towards the upper data track, and the track number recorded in the track ID part 4R is numbered from upper data track towards lower data track. However, the sequences of the track numbers may be reversed. Further, in the embodiment described, the track number starts from 0, but the minimum value of the track number is not limited to this. Figure 10(a) and (b) are schematic views illustrating optical cards according to a fourth embodiment of the present invention. Referring to Figure 10(a), the optical card has 2502 data tracks, whilst in Figure 10(b), the optical card has 1102 data tracks. These optical cards are the same as the optical card shown in Figure 9 (a) and (b) except that the number of data tracks and the start number of the track number is 2. Thus, referring to Figure 10(a), the maximum value of the track number is 2499 and a sum of track numbers 4L and 4R at a same track is 2497. Referring to Figure 10(b), the maximum value of the track number is 1099, and the sum of track numbers 4L and 4R at the same track is 1097. Referring to the optical card shown in Figure 10(a), where the track number recorded in track ID part 4R is defined as the reference track number of each data track, and the apparatus firstly reproduces the track number of track ID part 4L, the track number may be subtracted from 2497 to provide a reference track number. In case that the track number of track ID part 4L is 2497, the reference track number is provided as follows: 2497 - 2498 = -1 This value coincides with the reference track number recorded in track ID part 4R. Hereinabove, four embodiments of optical cards are explained for the information recording and/or reproducing apparatus according to the present invention. However, optical cards used by an information recording and/or reproducing apparatus according to the present invention, the information about the number of the data tracks may sometimes be recorded in same form (for example a recording position, recording method, etc.) so as to increase reproducing reliability of the information at the initial action. As described above, according to an information recording and/or reproducing apparatus of the present invention, by using an optical recording medium recorded with information about the number of tracks in the form of an optically detectable mark, it is able to prohibit an optical head from trying to access to a data track which does not exist on the optical recording medium because of the optical head's movement in the direction of crossing the tracks can be controlled according to the information about the number of the tracks reproduced and memorised at the initial action. Thus, there is provided an information recording and/or reproducing apparatus which is able to be used with various kinds of optical recording mediums having different numbers of tracks. In particular where the upper control means requests access to a track number which does not exist actually on the optical recording medium inserted into the information recording and/or reproducing apparatus, the apparatus prevents access of the optical head to the track. Thus, errors are prevented. It will be seen that according to the present invention, there is provided an optical recording medium on which can be identified the type of optical recording medium without providing a specific mark which would decrease the recording capacity of the optical recording medium. Further, according to the third embodiment of the optical recording medium, it is possible for an information recording and/or reproducing apparatus to identify a number of data tracks by recording a track number in track ID parts 4L and 4R which are numbered that the track numbers increase in one direction in the ID part 4L and increase in the opposite direction in the track part ID part 4R, the apparatus calculating the sum of the track numbers from the track ID parts 4L and 4R at the same data track. Thus, according to the present invention, there is provided an optical recording medium which can identify the number of data tracks to the information recording reproducing apparatus easily without providing a special mark which shows the type of optical recording medium. It will be appreciated that an optical recording and/or reproducing apparatus and an optical recording medium in accordance with the invention may take the form of a magneto-optical recording and/or reproducing apparatus and recording medium.

Claims: An apparatus for performing at least one of the functions of recording information on and reproducing information from an optical recording medium having a plurality of tracks, comprising: an optical head (30) for irradiating the optical recording medium (1) with a light spot and detecting reflected light from the optical recording medium (1); means (36) for moving the light spot to a desired track; and means (33) for controlling the apparatus to read information about the number of tracks on the optical recording medium (1), and to memorise the information as an initial action, and then for controlling the moving means (36) to move the light spot within a range dependent on the memorised information, the apparatus being characterised in that the means (33) for controlling the apparatus is arranged to compare a track number to be accessed with the said range, and to produce an error signal without moving the light spot towards the track when the track number is not within the said range. An apparatus according to claim 1, wherein the tracks are parallel with each other, and the means (36) for moving the light spot is arranged to move the optical head (30) in the direction in which the optical head (30) crosses the tracks (2). An apparatus according to at least one of the preceding claims, wherein said information is recorded as optically readable information and said apparatus includes means for reading said information optically. A method of performing at least one of the operations of recording information on and reproducing information from an optical recording medium provided with a plurality of data tracks (2) having information about the number of tracks (2), the method comprising the steps of: providing an apparatus effective to perform at least one of the functions of recording information on and reproducing information from said information recording medium, the apparatus comprising: a driving means effective to move a light spot to a desired data track (2), inserting (101) said information recording medium (1) into the apparatus; reproducing the information (step 102) and memorising (step 103) the range of accessible tracks (2) on the information recording medium (1) according to the information on the tracks (2); comparing (step 201) a track address which is indicated by an input signal to the apparatus to be within the range (step 205); moving the light spot to a data track (2) having the track address when the track address is within the range to record information; and sending out an error signal (step 205) without moving the light spot when the track address is not within the range.

Inventors: HOSOYA HIDEKI, HOSOYA, HIDEKI, HOSOYA, HIDEKI, C/O CANON K.K.
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1994
Main classification: G06K7
IPC codes: G06K7